If Jane Austen had written fairy tales, they might read like Susanna Clarke's "Jonathan Strange & Mr. Norrell." Using the same alternate version of the early 1800s in which she set her elegant, astringently witty short story "The Ladies of Grace Adieu," Clarke creates a world in which the pastel remnants of a much wilder medieval magic are studied by eccentric country gentlemen.

"Strange" lives up to all the enticing promise of Clarke's earlier work. Her deftly assumed faux-19th century point of view will beguile cynical adult readers into losing themselves in this entertaining and sophisticated fantasy.

"It has been remarked ... " begins an early chapter, "how kindly disposed the world in general feels to young people who either die or marry. Imagine then the interest that surrounded Miss Wintertowne! No young lady ever had such advantages before: for she died upon the Tuesday, was raised to life in the early hours of Wednesday morning, and was married upon the Thursday; which some people thought too much excitement for one week."

The aforesaid Miss Wintertowne is the beneficiary of the reclusive Mr. Norrell's efforts to astound government officials with his magical prowess. His initial public demonstration caused the stone statues of York Cathedral to come to life, but this was in a location remote from London.

To become the talk of cabinet meetings, Mr. Norrell resurrects Miss Wintertowne, a high-ranking politician's fiancée  though in doing so he resorts to a sort of magic he outwardly condemns as "deplorable" and "pernicious."

Mr. Norrell, "a small man of no particular personal attractions" and a "dry little heart," has ensured by devious means that he is the only practicing magician in England. Now he strives to make magic as dull and respectable as himself.

Susanna Clarke

In this he's opposed  at first gently and respectfully  by his sole pupil, Jonathan Strange. The "almost handsome" inheritor of a Shropshire estate who has tried his hand at everything else, Strange stumbles upon magic in the person of a homeless street-conjuror sleeping under a hedge. The conjuror bears a prophecy concerning England's two magicians (though thanks to Mr. Norrell there's currently just one), and three stolen spells, the third of which Strange surprises himself by performing correctly. Because he can't learn his new profession from books (Mr. Norrell has bought them all), Strange presents himself to his rival for tutoring.

Impressed with the younger man's entirely off-the-cuff ensorcelling of a book's reflection, Mr. Norrell goes against his followers' expectations and takes him on. Though from the start they disagree about such basic questions as the employment of fairy servants and the importance of the 300-year reign of the legendary Raven King, student and teacher form a strong, complex relationship, with depths and contradictions as true-to-life as any depicted in so-called realistic fiction.

This relationship is the sturdy hinge on which the novel swings. The hinge's burden is in some ways a heavy one. Physically speaking, for instance: "Strange" is 782 pages long. And it's the result of more than 10 year's imagining, writing and research, a creation so densely detailed that the footnotes with which the text is larded pique rather than satisfy the reader's interest.

But in other ways, the book is light as a shadow. Shadows fill the illustrations by Portia Rosenberg, as apt as Edward Gorey's for Dickens' "Bleak House." Shadows dim the mirrors through which Strange travels on his perilous missions to the Otherlands; shadows and feathers haunt the street sorcerer's prophecy: "... I came to them in a flock of ravens that filled the northern sky at dawn ... I sit upon a black throne in the shadows but they shall not see me. The rain shall make a door for me and I shall pass through it ... "

There's a tension between poetic visions such as these and the period's lovingly detailed mundanities that echoes the growing conflict between Mr. Norrell's ambition to be England's Foremost Magician and Strange's longing for a return to the miraculous times of the Raven King.

Of course, in a novel of "Strange's" scope there are other themes, other subplots, other finely drawn characters  the obscurely menacing "gentleman with the thistle-down hair," the politician's "Negro" butler Stephen Black  but Clarke's most impressive show of authorial skill is in how she resolves this tension without destroying it.